The multicenter concept for establishing a network of maternal-fetal medicine units is a unique opportunity to conduct clinical trials involving patient care systems. By establishing programs in several large units, answers to questions may be obtained efficiently, within short time periods, and at minimum expense since duplication of efforts in uncoordinated smaller studies can be eliminated. The Columbia University application documents a large patient population, with an established data collection system incorporating obstetrical and neonatal centers of excellence and with depth of research in endocrinology, epidemiology, infant development and nurse midwifery. Two examples of research protocols have been submitted. In the first the treatment of the very low birthweight fetus and the prevention of intraventricular and cerebral hemorrhage is pursued. In the second protocol a system designed to prevent the onset of premature birth is modeled. Both are considered of interest and meet the specific guidelines for the collaborative project.